Photographic-printing process



J. E. THORNTON.

PHOTOGRAPHIC PRINTING PROCESS., AVPPLlcAnoN FILED SEPT. I3, 191s.

1,360,156. 1 PatentedN0v.23,192o.

Quang,

UNITED STATES PATENT OFFICE.

JOHN EDWARD THORNTON, 0F WEST HAMPSTEAD, LONDON, ENGLAND, ASSIGNOR TO JOHN 1OVDEN OBRIEN, 0F MANCHESTER, ENGLAND.

PHOTOGRAPHIC-PRINTING PROCESS.

Specification of Letters Patent.

Patented Nov. 23, 1920.

Original' application filed Iunev30, 1915, Serial No. 37,323. Divided and this applicationled September 13, 1918. Serial No. 253,969.

To all whom it 'may concern:

Be it known that I, JOHN EDWARD THORN- TON, a British subject, residing at West Hampstead, London, England, have invented certain new and useful Improvements in and Relating to Photographic Printing Processes, of which the following is a specification.

. This invention relates to the manufacture or production of transparent cinematograph films.

In my prior Patent No. 1,288,753, granted December 24, 1918 and of which this application is a division, I have described a method of manufacture in which the image of the successive pictures on the cinematograph film is broken up into or composed of a large number of screen markings of very fine dots and which when magnified by projection will show a grainy image lon the screen, which on account of the enlargement would be very pronounced.

The object of this invention is to produce a transparent cinematograph lilm in which the color patternof lines, dots or grain is rendered invisible or their appearance reduced to a minimum and which by the law of persistence of Vision will give to the observer when projected in succession on a screen the impression of full tone grainless pictures.

It consists'in disposingthe dots, lines orv grains in a different position or varying the position of the dots, lines or grains on the corresponding part of the image on each succeeding picture of the series throughout the length of the film, whereby when the pictures are projected in rapid succession upon a screen the different position of the dots, lines or grains of which the picture is composed, .and the persistence of vision of the observer, will Obliterate the appearance of dots lines or grains, and give to the observer the impression of full tone or grainlesspictures. i

The invention will be equally applicable to monocolor pictures printed at one exposure or impression or to multi-color pic- V tures printed superlmposed at two or more Y exposures or impressions. p I t In the printing of clnematograph films, 1t

is necessary toprovide a negative each pic-- ture of the series thereon being printed through the interventiony of a screen which breaks the picture up into a number of dots lines or grains, and in the ordinary way of production each dot line or grain produced by the screen would in each succeeding picture occupy a correspondingposition on the image.

Now by this invention in producing the negative as each picture is successively produced the interposed screen is moved a slight distance in one direction or another, so that While the picture images remain relatively unmoved the screen markings of dots lines or grains which comprise the image vary in relative position from one picture to the next, thereby giving the result desired.

In the accompanying drawing Figure 1 is a diagrammatic view showing a lmethod of producing a positive print from a dot negative;

Fig. 2 represents a cross section of'a print obtained from the dot negative;

Fig. 3 is a diagrammatic view showing a method of obtaining a dot negative such as that shown in Fig. 1;

Fig. 4 is a diagrammatic view showing a method of arranging the dots in different positions in the successive pictures of the final print; and

Fig. 5 is a diagrammatic view showing the relative positions of the dots of the pictures when projected in succession upon a screen.

In carrying out the invention according to the preferred procedure, the film, or other support 1, is first coated with a sensitized colloid 2, such as gelatin, in which pigment or the desired dye has been incorporated.

The sensitized film is exposed from the front for the requisite period of time to print through to the base, under a screen printing negative 6 of a special type hereinafter described, then developed, washed and dried. If the colloid be gelatin, hot water is lused for development. The development is .cause of the breakingup of the image into a large number of very fine dots, by the use of a screen printing negative, known as a process negative 1n which the image is -composed of a similar number of small dots orlines, such negatives being used in halftone block making and other-well known mechanical processes.y f

end coloied eoiloid, an@ iepieseiis iii seeiou the peint obtaiue@ by exposue the'eof through suoli o, neg-Mi ghe said. pin being composed of dois height and depth bi vali," ness in inverse ratio Je fw tive and the Whole of h the image ae iiisoiubie o zhe soluble points hai'iiw Washed away duiiiig sie The seieen piiiiziiiff l piefeiabiy, 4 ss' shown. Figf, by placing a continuous eiuematogrziph *5V 8 mooie of the oiigiiial Co iiuous oie i" e powerful iigL i oiiei with s (oo s tween them. lpoi iiim so exposed result, it boei aye eouiitepu they consi o1 sizes mui eioseiiess7 in bi'oken iones ins` and ibis im msj produ@ d y"ie ze ufeiifi;

reduce 'ziiis eli-sei; to s lui by siiiiing the iuied. soieeii beh-veen die enposuie of; successive 'nnen ing the epodueed (new leli ing negeive7 is shown il iiieu the einemeogra ed or epi'ociu e'i "from etive such dos, iines oi' jected on the seeen subssuU sented diagmiiimatieelly in i i in conjunction wih tixeii mouiei ence upon ehe sei-een wii ieiuie lines oi' gi'ains invisible 13o she eye ei i server thiough 'the persis'i-euce o^ ing he impression oi a ui toze qiuiiiies: picture.

To produce muiti-eoloie timispziieua lms, two of moie negatives we Dfepeefione for each @doi-With the dois, iin-es oe grains theieui in a diffeieiiiz position reistive to the image in each succ-ee longitudinally of the iim, in i; hereinbeore deseiibed, and Ei'om hese negatives the ti'anspaisen ilm is pziiiec ov sueeessive eziposues er impressions in different eoiois superimposed one upon he ofihei'.

What Claim as new imeuiion and desire pioee by Letters L the poduf-iioii oi primed "aanspori' cliiemsogi'aph films i? which iiie imiosed. of L f'i of dots iiiies mehod of ik lering ehe petl L 3 observe?) when e lie eye o; l

e poieee l iii succession upon fj/ing iie posi- Hunan ouin es thereon o. piuizi. f' of pi'iniings sind iepieseued in (ios lines or moter'zi, SLiie seid dots lrferent relan in relaion io the picture image voi' eheh succeeding; pieure 'of' the. series.

in testimony Wueieof have hereunto set my hand in preseiiee of wo subscribing Wifmesses.

J 'iifitiesses J. UWDEN @BRIEN Geo. BRIEN.

'EDWARD TeioiiNToN. 

